This study will examine the effects, over time, of local law enforcement efforts at reducing drug use and drug trafficking on: property crime, violent crime, local heroin and cocaine prices, and drug use indicators in New York City. Ours will be a time-series study, examining monthly observations, beginning in 1970. We will examine variations-in police policies such as: the total number of officers, the number of officers specifically assigned to the Narcotics Division and other special units, overall arrest rates, the allocation of arrests between drug and non-drug felony crimes, the allocation of drug arrests between the Narcotics Division versus other police units, the allocation of drug arrests between felony and misdemeanor offenses, and the allocation of drug arrests between heroin, cocaine, and other drugs. We employ a dynamic time series approach and incorporate some of the recent advances in the econometric literature to examine these interrelationships. This dynamic modelling allows us to examine not only the contemporaneous relationships between the variables, but it also allows us to assess the timing of the reactions of variables to each other. We will apply these techniques to a newly constructed time series of data on crime, arrests, police personnel, labor force and poverty variables, demographic variables, drug prices, and a variety of drug use indicators for New York City covering the two decades beginning in 1970.